Role of PPase-SE in Geotrichum klebahnii, a yeast-like fungus able to solubiliza pectin

ROJAS, N.L.;; CAVALITTO, S.F; HOURS R.A.

San Miguel Tucuman

Simposio; Simposio Internacional de Biotecnología. II Simposio Argentino Italiano de Bacterias Lácticas; 2004

Protopectinases (PPases) constitute a heterogeneous group of enzymes able torelease soluble pectin from insoluble protopectin in plant tissues. Geotrichum klebahnii(ATCC 42397), a yeast-like fungus, produces PPase-SE, an extracellular enzyme withendopolygalacturonase (EC 3.2.1.15) activity. The potential use of PPase-SE on pectinextraction and maceration of plant tissues has been reported. Here, it was studied thecapacity of G. klebahnii to use different pectins as carbon and energy sources (CES) andalso its capacity to release pectin from lemon peel.The strain was unable to use pectin from different origins and pectin relatedsubstances as CES. In addition, it produced PPase-SE in a glucose containing medium.A culture was used for the extraction of pectin from lemon peels. Pectin wasenzymatically extracted, simultaneously with lemon peel maceration, yielding 3.7 g of(dry) pectin per 100 g of (wet) lemon peel. Finally, extracted pectin was notmetabolized by the strain.It was concluded that G. klebahnii uses PPase-SE to macerate and, in this way, toinvade plant tissues to get the soluble sugars used as CES without metabolizingsolubilized pectin.